<div class="box">
  <h3 style="text-align: center;margin-bottom: 8px;">这是父组件</h3>
  <div style="margin-bottom: 8px;">
    <button (click)="runChildRun()">获取子组件实体</button>
  </div>
  <a03-child #childDom></a03-child>
</div>
